Core drill bit



Oct. 3, 1950 o, s 2,524,570

CORE DRILL BIT Filed Aug. 30, 1946 wmxxx ORV/4L5 P lPRs 5K TTO/P/VEYPatented Oct. 3, l50

v UNITED STATES "PATENT OFFICE CORE DRILL BIT Orville Phipps, AdamsCounty, near Denver, Colo.

Application August 30, 1946, Serial N 0. 693,985

This invention relates to bits for coredrills of the type commonlyemployed for the'severance and extraction of continuous cylindricalsamples of earth strata from considerable depths below the earthsurface, and has as an object to provide an improved bit adapted tofunction as the cutting or core severing element of conventionalcore-type drill rigs.

A further object of the invention is to provide an improved core drillbit characterized byhigh operative efiiciency and amenability to simple,convenient, repetitious reconditionin in the field.

A further object of the invention is to provide an improved arrangementand operative combination of elements constituting a relativelyinexpensive core drill bit of enhanced performance and sustained cuttingefiiciency.

A further object of the invention is to provide an improved core drillbit that is self-guiding for the development of a straight, true boreand the consequent production of a straight core accurately representingthe penetrated strata.

3 Claims. (01. 255-72) A further object of the invention is to provide 7ate sticking or binding of the bit and twisting I or like deformation ofthe core.

A further object of the invention is to provide an improved core drillbit convenient of substitution for conventional and hitherto known bitsin and for operative association with rigs and equipment now in use,Which in'no way alters or interferes with the operation of conventionalcore lifting adjuncts, which is removable and re-' placeable relative tothe usual actuating drill stocks or lines, and which is susceptible ofready production in a range of sizes and specific forms to meet allfield requirements.

With the foregoing and other objects in view, my invention consists inthe construction, arrangement, and combination of elements hereinafterset forth, pointed out in my claims, and illustrated by the accompanyingdrawing, in which:

Figure 1 is an end elevation of a typical core drill bit embodying theprinciples of the invention. Figure 2 is a side elevation of the bitconstruction according to Figure 1. Figure 3 is a section axially of theimproved bit taken substantially on the indicated line 33 of Figure 1,Figure 4 is a fragmentary side elevation of the cutting end portion ofthe improved drill bit as slightly modified within the contemplation ofthe invention.

Core drill rigs have long been used to explore strata and operate to cutout an annular or tubular bore from about a cylindrical body of thepenetrated strata and to lift sections of said body to the surfaceWithout alteration in the original relation of the intersected beds,folds, and formations. Such rigs include a verticallydisposed,continuous line or string of tubular sections power-rotatable about itsaxis and armed at its lower end with a bit presenting a lower annularmargin, frequently inset with diamonds, which does the actual cutting ordrilling as .it is caused to rotate with the line or string and throughwhich the developed core rises within the line or string for elevation,through the agency of lifting adjuncts, with the line or string as thelatter is withdrawn from the bore. Bits for the arming of the line orstring lower end, as heretofore constructed, are expensive if at allefiicient in penetrative effect, short-lived in use, and difficult ofreconditioning in the-field, and it is to the correction of these primedeficiencies of theusual bits that the improvements of the instantinvention are directed.

In the construction of the improved bit, .as shown, the numeral l0design-ates a tubular body portion formed from any suitable,readily-workable material, such as tool steel, in any convenient mannerand to the general form, outline, and proportions common to conventionalbit bodies. The body It preferably has a maximum exterior diameterequalling that of the string or line wherewith it is to be associatedfor actuation, an interior diameter the same as or slightly less thanthat of the said string or line, it being within the contemplation ofthe invention that the body bore may be very slightly conical instead oftruly cylindrical, as is common practice in the construction ofconventional drills, a right cylindrical portion adjacent and formingthe cutting edge end of the bit, means, such as threads ll, eitherexternal or internal, formed at its end remote from the cutting edge toengage and cooperatewith complementary means on the drill line or stringfor the removable and replaceable mounting of the bit assembly on and inrotatably driven association with the line or string, and a radialthickness at its cutting edge end adequate to resist and withstand theforces to which the bit is subjected when operated. All of the foregoingis standard practice, variable as to size, form, and proportions to meetthe wide range of associated equipment variation and field requirements,and in and of itself forms no part of the instant invention save insofaras it provides the support and mounting essential for the improvedcutting edge wherein the invention resides.

It is known that certain non-ferrous alloys, such as one comprised fromtungsten, titanium, tantalum, nickel, and cobalt, are exceedingly tough,approach the diamond in hardness, do not easily chip or fault, aresusceptible of being ground, and are amenable to welding without loss ordestruction of their characteristic properties. Such alloys can beformed to desired size and shape, securely attached to and permanentlyassociated with forms and shapes of other metals, and ground andreground while mounted, without need for heat-treating, forging, ortempering, hence are ideally suited for use as durable, longwearing,rehabilitatable teeth to cut through refractory material encountered bythe cutting edges of core drill bits, and are so used, in a novel andeffective manner, in the improved bit of the invention.

For rapid-cutting, long-wearing, repetitiouslyreconditionable mountingof the non-ferrous alloy teeth on the body Ill, the cutting edge end ofsaid body is divided into a plurality of uniform, angular segments,eight such being shown in the views of the drawing, and each of saidsegments is worked to present a flat, smooth face, paralleling the bodyI axis irf the showings of Figures 1, 2 and 3, on its end leading in thedirection of 'bit rotation and a curved or inclined, axially-projectedend surface I2 smoothly interconnecting the outer end of its flat facewith the inner end of the flat face leading the next succeeding segment.The segment flat faces, which serve as abutments for the mounting andoperative support of the alloy bit teeth, may be radial of the body I0,tangent to a small circle concentric with said body I0, parallel to thebody I9 axis in either radial or tangential disposition, or inclined tothe said body axis with their outer ends leading in overhang ng relationwith their inner ends, as shown in Figure 4, according to the nature ofthe material to be penetrated and the preferences of the user, eacharrangement having certain functional characteristics which recommend itfor use in particular occasions Completing the improved bit, a pluralityof identical blocks l3 of the characteristically hard, tough, abrasiveresistant, alloy material, one for each of the segment fiat faces, isformed, each of said blocks having a length exceeding the depth of asegment flat face, a width exceeding the width of a segment flat face, athickness proportioned to the bit size and alloy material properties toinsure adequate strength against shear, and a sub- I stantiallyrectangular outline. As so formed, a block I3 is mounted against andsecurely welded to each of the segment fiat faces, the inner end of eachblock basing solidly in the correspondingly-worked angle between a.surface I2 and the next succeeding fiat face, the outer end of eachblock I3 projecting axially of the body I0 beyond the outer margin ofits mounting face, and side margins of each block I3 extending,respectively inwardly and outwardly, beyond the adjacent cylindricalwalls of the body I 9 to define planes and cutting corners effectivelyparallel to, longitudinally of, and inwardly and outwardly spaced fromthe said body walls. With the blocks [3 mounted on and secured to thebody I0 segments as shown and described, the outer, axiallyprojectingends of said blocks are ground to lie and work in a common operatingsurface, preferably that of a flat cone coaxial with the body I!) andhaving its apex directed outwardly of and away from the bit assembly,and the outer end of each block !3 is beveled and inwardly andrearwardly inclined, in the direction of bit rotation, to provide achisel-type cutting edge I4 in the plane of the block exposed surfaceand for engagement with the material to be penetrated as the bitassembly is rotated.

When operated in the usual manner on and as the terminal extension of apower-rotated drill string or line, the cutting effect of the improvedbit is developed through, and solely by means of, engagement of theblock I3 outer ends and inner and outer side margins with the materialto be penetrated, all of the wear incident to the drilling operationbeing imposed on the alloy material blocks or teeth which are natured toresist and withstand it in a manner to protect the less resistant bodyIll against any substantial impairment. The parallel, inwardly andoutwardly extending side margins of the blocks I3 cut and form acylindrical channel wherein the following body It] and drill string orline is freely accommodated without tendency to bind and provideclearances through which the drillings may pass without adversecompacting thereof. The flat cone disposition of the cutting edges I4cooperates with the block side margin alignment to center and guide thetool in the development of a straight, true bore, concentrates the biteof the tool at the inner margin of its cutting orbit, and acts to movethe drillings outwardly of the bore and away from the internallyaccommodated core. Obviously, the effective bite of the tool is afunction of the block I3 rake, variable from neutral through severaldegrees of positive inclination at the time of bit manufacture, and ofthe tooth cutting edge bevel, which latter may be varied in the field bychanging the angle to which the individual teeth are ground andsharpened. Reconditioning, or dressing, of the tool for rehabilitationafter use is a simple matter of grinding, readily accomplished in thefield, and may be repeated at need to utilization of substantially theentire effective depth of the blocks l3, the segment surfaces I2 beingground away as the block length is reduced, thus contributing aremarkably long life of practical use to a given bit unit.

Since changes, variations, and modifications in the specific form,construction, and arrangement of the elements shown and described may behad without departing from the spirit of my invention, I wish to beunderstood as being limited solely by the scope of the appended claims,rather than by any details of the illustrative showing and foregoingdescription.

I claim as my invention:

1. A core drill bit comprising a tubular body of tractable metalconnectible as a coaxial terminal extension on and for rotation with adrill string, a succession of uniformly spaced, fiat, axially-directedabutments formed in the annular working end of said body to face in thedirection of bit rotation, and a block of hard, tough, abrasiveresistant alloy material welded to and in covering relation with eachabutment face to project in abutment-backed support of its major area atits side and outer end margins beyond the adjacent body surfaces;together with notches intersecting the body annular working end betweenadjacent said blocks and each extending at an angle from the rear faceof a leading alloy block to the root of a trailing block to therebyfully uncover the leading face of the trailing block and provide asingle circulatory path for cuttings and coolant.

2. A core drill bit comprising a tubular body of tractable metalconnectible as a coaxial terminal extension on and for rotation with adrill string, a succession of uniformly spaced, flat abutmentslongitudinally intersecting the annular working end of said body to facein the direction of bit rotation, and a cutting element of hard, tough,abrasive resistant alloy material welded to and in covering relationwith each abutment face, each of said elements consisting of asubstantially rectangular block having parallel side margins, 21 widthexceeding the-body annular wall thickness, and a length exceeding theabutment depth, and is disposed in abutment-backed support of its majorarea for projection of its side and outer end margins beyond theadjacent body surfaces; together with notches intersecting the bodyannular working end between adjacent said blocks and each extending atan angle from the rear face of a leading alloy block to the root of atrailing block to thereby fully uncover the leading face of the trailingblock and provide a single circulatory path for cuttings and coolant.

3. In a core drill bit having a tubular body of tractable metalconnectible as a coaxial terminal extension onand for rotation with a.drill string, a succession of uniformly spaced, flat abutmentslongitudinally intersecting the annular working end of said body to facein the direction of bit rotation, and a cutting element consisting of asubstantially rectangular block of hard, tough, abra sive resistant,non-ferrous material amenable to welding and grinding aflixed, in a facearea exceeding that of the individual abutments, to and in coveringrelation with each said abutment to project in abutment-backed supportof its major area at its outer end and side margins beyond the adjacentbody surfaces; together with notches'in-u tersecting the body annularworking end between adjacent said blocks and each extending at an anglefrom. the rear face of a leading alloy block to the root of a trailingblock to thereby fully uncover the leading face of the trailing blockand provide a single circulatory path for cuttings and coolant.

ORVILLE PHIPPS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

